Babies Are Larger After Ban on 2 Pesticides, Study Finds

By RICHARD PÉREZ-PEÑA

Published: March 22, 2004

Pregnant women in upper Manhattan who were heavily exposed to two common insecticides had smaller babies than their neighbors, but recent restrictions on the two substances quickly lowered exposure and increased babies' size, according to a study being published today.

The researchers, led by a team from Columbia University, looked at babies born to women living in Harlem and Washington Heights, and divided them into four groups, based on the amounts of the pesticides chlorpyrifos and diazinon found in the mothers' blood and umbilical-cord blood. In the group with the highest levels, babies were, on average, 6.6 ounces lighter and one-third of an inch shorter than those in the group with no measurable amount of the insecticides in the blood.

The authors write that theirs is the first reported study to show a link between umbilical-cord levels of these two pesticides and newborn size. The researchers added that it was also the first to document an improvement in birth size from curtailing use of a pesticide.

The study was part of a long-running project by Columbia researchers to gauge the effects of urban pollution on mothers and children. Dr. Frederica P. Perera, director of that effort, said the new results were significant because "birth weight is a very good predictor of later health and development of children, including physical development, mental development and school performance."

Chlorpyrifos and diazinon were once found in dozens of over-the-counter products and were heavily used by professional exterminators. The federal Environmental Protection Agency banned them from indoor use in stages, from 2000 to 2002, though both pesticides are still used in agriculture and are commonly found on produce.

The new study of 314 babies, being published in the journal Environmental Health Perspectives, found that the ban had a notable effect on pesticide exposure and infants' size.

"It was very marked, and pretty immediate," said Dr. Robin M. Whyatt, the principal author of the study and an assistant professor at the Mailman School of Public Health at Columbia.

Among children born from 1998 to 2000, about one-third fell into the high-exposure group. But of those born in 2001 and 2002, just one out of 77 was in that group, Dr. Whyatt said. As pesticide levels fell, she said, infant size rose.

What made that change all the more remarkable, she said, is that while exposure to the pesticides dropped significantly in 2000, 2001 and 2002, it did not suddenly fall to zero. The E.P.A. began phasing out sales for residential use in 2000 for chlorpyrifos and 2001 for diazinon, and many stores voluntarily took the products off their shelves before they were required to do so.

But the total bans on indoor use did not take effect until the end of 2001 for chlorpyrifos and the end of 2002 for diazinon. Surveys by Columbia found that many stores in minority areas were still selling products with those pesticides as late as mid-2003.

"Our data indicate that the exposure levels are still going down," Dr. Whyatt said. "We may continue to see added benefits of this ban over time."

Since 1997, Columbia's environmental health project has measured the effects of smoking, air pollution and other factors on women in upper Manhattan and their children. Dr. Perera said the researchers planned to track the children over many years, as they go through school, to see if exposure to pesticides and other pollutants can be shown to affect mental development and academic performance.

The women who participate, all of them black or of Dominican descent, were recruited from the prenatal clinics at Harlem Hospital and New York-Presbyterian Hospital. In the most recent study of pesticide levels, women were excluded for other factors that also affect birth weight.